As prostaglandin (PG)E.sub.2 agonists, many compounds are known including PGE.sub.2 per se or its derivatives. However, no compounds which antagonize for PGE.sub.2 or inhibit PGE.sub.2 activity were known until now.
PGE.sub.2 is known as a metabolite in the arachidonate cascade. It is known that PGE.sub.2 has an uterine contractile activity, a pain-inducing effect, a promoting effect of digestive peristalsis, an awaking effect, a suppressive effect of gastric acid secretion, a hypotensive activity etc. PGE.sub.2 exhibits the following expected effects:
To antagonize PGE.sub.2 means to suppress the effects above mentioned. Therefore PGE.sub.2 antagonists are considered to inhibit uterine contraction, to have an analgesic action, to inhibit digestive peristalsis, to induce sleep, etc. Therefore, PGE.sub.2 antagonists are considered to be useful as analgesics, antidiarrheals, sleep inducers or for the preventive of abortion.
To agonize for PGE.sub.2 means to promote the effects above mentioned, so PGE.sub.2 agonists are considered to promote uterine contraction, to promote digestive peristalsis, to suppress a gastric acid secretion, to lower blood pressure. Therefore, PGE.sub.2 agonists are considered to be useful for abortion, cathartics, antiulcer, anti-gastritis, antihypertensivity.